Search Results (32)

This study systematically examines the influence of Zn addition (≤0.6 wt.%) on the microstructure and mechanical properties of Mg-2Al-0.8Sn-0.5Ca (wt.%) alloys. Minor Zn alloying marginally increases secondary phase fraction in as-cast alloys, with complete Zn dissolution achieved after solution treatment and asymmetric severe shear extrusion. Extruded alloys exhibit non-monotonic strength evolution with Zn content, peaking at 0.2 wt.% Zn (yield strength ≈ 235.1 MPa, ultimate tensile strength ≈ 289.2 MPa), while elongation reaches 16.1%. This strength enhancement originates from synergistic grain boundary, solid-solution, and dislocation strengthening mechanisms. These results demonstrate Zn’s critical role in optimizing the strength-ductility balance of rare-earth-free magnesium alloys. Full article

The influences of the addition of Ca, Zn, and Zr on the corrosion behavior and mechanism of as-homogenized Mg-3Sn (T3) alloys in a 3.5% NaCl solution were systematically investigated via hydrogen evolution, mass loss, and electrochemical tests. The results indicated that the addition of Ca resulted in a decrease in the corrosion resistance of the T3 alloy. However, the subsequent addition of Zn and Zr could enhance the corrosion resistance of the Mg-3Sn-1Ca (TX31) alloy. The primary cause for the decline in the corrosion resistance of the TX31 alloy was that Ca altered the type of the second phase and the corrosion mechanism of the T3 alloy. This was attributed to the fact that the addition of Ca in the T3 alloy induced the precipitation of the CaMgSn phase and inhibited the precipitation of the Mg₂Sn phase. Simultaneously, both the average grain size and the area fraction of the second phase increased, which provided more initiation sites for pitting and accelerated the corrosion of the alloy. The addition of Zr in the TX31 alloy could remarkably refine grains, inhibit anodic corrosion, and improve corrosion resistance. Nevertheless, the corrosion resistance of the Mg-3Sn-1Ca-1Zr (TXK311) alloy was still inferior to that of the T3 alloy. In this study, the Mg-3Sn-1Ca-1Zn (TXZ311) alloy exhibited the best corrosion resistance, with a hydrogen-evolution corrosion rate of 2.82 mm·year⁻¹. This was because the addition of Zn refined the grains of the TX31 alloy and facilitated the formation of a relatively stable passivation film, which effectively prevented the intrusion of Cl⁻, thereby enhancing the corrosion resistance of the alloy. Full article

This study conducted a systematic investigation on how Ca content affected Mg-6Al-1Sn alloys as anodes for Mg-air batteries in terms of their microstructure, electrochemical corrosion behavior, and discharge performance. According to the investigation results, incorporating Ca induces the formation of blocky β-Mg₁₇Al₁₂ phases containing Ca and refines the grain structure. Compared to Mg alloys without Ca, the alloys with Ca exhibit significantly improved self-corrosion resistance because the preferential enrichment of Ca at the grain boundaries within β-Mg₁₇Al₁₂ phases reduces the potential difference between β-Mg₁₇Al₁₂ phases and Mg matrix. Consequently, galvanic corrosion is mitigated, together with the effective suppression of the self-corrosion reaction of Mg anodes. Additionally, Mg alloy shows a higher anode utilization efficiency with Ca content. The combined results indicate that Mg-6Al-1Sn-0.5Ca alloy exhibits superior self-corrosion resistance and discharge properties vs. other tested compositions. Furthermore, the Mg-air battery using Mg-6Al-1Sn-0.5Ca alloy as the anode demonstrates a heavier average discharge potential and a utilization efficiency of 71.12%, which is 7.56% higher than Mg-6Al-1Sn alloy. Full article

TX31 (Mg-3Sn-1Ca) is an alloy with promising future applications. This study enhances the corrosion resistance of the TX31 alloy through the addition of Zr and Zn and compares the effects of individual Cu addition and Zn/Cu composite addition on the corrosion resistance of the TX31 alloy. This study investigates the corrosion properties of TX31 alloys, focusing on the effects of the grain size, second phase, corrosion product film, and texture intensity. The addition of Zr and Zn changed the second-phase area fraction, while Cu introduced a new Mg₂Cu phase. The TXZ311 alloy (Mg-3Sn-1Ca-1Zn) exhibited the best corrosion resistance, with a corrosion rate as low as 1.68 mm·year⁻¹, a significant reduction compared to other alloys. This improvement is attributed to its higher fraction of high-angle grain boundaries (HAGBs) and the enhanced stability of the corrosion product film. The TXK311 alloy (Mg-3Sn-1Ca-1Zr) showed superior corrosion resistance, with a rate of 2.97 mm·year⁻¹, due to its uniform and fine grain structure. In contrast, the TX31 alloy had the poorest corrosion resistance, with a corrosion rate of 3.66 mm·year⁻¹, due to its bimodal microstructure. The addition of Cu in the TXC311 (Mg-3Sn-1Ca-1Cu) and TXCZ3111 (Mg-3Sn-1Ca-1Cu-1Zn) alloys resulted in micro-galvanic corrosion between α-Mg and Mg₂Cu, which decreased the corrosion resistance. Full article

This study systematically investigates the influence of the composite addition of Ce, La, and Ca elements on the microstructure evolution and mechanical properties of Mg-3Zn-1Mn/Sn (wt.%) alloys. It indicates that the strength of Mg-Zn-Mn series alloys is superior to that of Mg-Zn-Sn series alloys, due to the stronger restriction of nanosized Mn particles on the recrystallization process and grain growth compared with Mg₂Sn phases. The addition of the Ca-La-Ce elements significantly enhances the strength of the Mg-3Zn-1Sn alloy (YS increased by approximately 92.5%, UTS increased by approximately 29.2%, and EL decreased by nearly 52.2%), while for the Mg-3Zn-1Mn alloy, a balanced effect on both the strength and performance can be achieved. This difference mainly lies in the more pronounced refined effect on the grain size and the formation of a bimodal grain structure with strip-like un-DRXed grains and surrounding fine DRXed grains for the Mg-3Zn-1Sn alloy. In contrast, the addition of the Ca-La-Ce elements has a less obvious hindrance on the recrystallization process in the Mg-Zn-Mn series alloy, while significantly weakening the extrusion texture while refining the grains. Through in-depth characterization and experimental analysis, it is found that Sn and Ca can promote the formation of brittle and fine secondary phases. A nanoscale Sn phase (Mg₂Sn phase) is more likely to accumulate at the grain boundaries, and the size of the nanoscale Ca₂Mg₆Zn₃ in Mg-Zn-Mn series alloys is finer and more dispersed than that in Mg-Zn-Sn series alloys, thus strongly hindering recrystallization and refining the recrystallized structure of the alloy. Full article

The interface connects the reinforced phase and the matrix of materials, with its microstructure and interfacial configurations directly impacting the overall performance of composites. In this study, utilizing seven atomic layers of Mg(0001) and Ti(0001) surface slab models, four different Mg(0001)/Ti(0001) interfaces with varying atomic stacking configurations were constructed. The calculated interface adhesion energy and electronic bonding information of the Mg(0001)/Ti(0001) interface reveal that the HCP2 interface configuration exhibits the best stability. Moreover, Si, Ca, Sc, V, Cr, Mn, Fe, Cu, Zn, Y, Zr, Nb, Mo, Sn, La, Ce, Nd, and Gd elements are introduced into the Mg/Ti interface layer or interfacial sublayer of the HCP2 configurations, and their interfacial segregation behavior is investigated systematically. The results indicate that Gd atom doping in the Mg(0001)/Ti(0001) interface exhibits the smallest heat of segregation, with a value of −5.83 eV. However, Ca and La atom doping in the Mg(0001)/Ti(0001) interface show larger heat of segregation, with values of 0.84 and 0.63 eV, respectively. This implies that the Gd atom exhibits a higher propensity to segregate at the interface, whereas the Ca and La atoms are less inclined to segregate. Moreover, the electronic density is thoroughly analyzed to elucidate the interfacial segregation behavior. The research findings presented in this paper offer valuable guidance and insights for designing the composition of magnesium-based composites. Full article

The microstructures and mechanical properties of Mg–3Sn–0.1Ca–xMM (mischmetal, x = 0.3, 0.6, and 0.9 wt.%) alloys were investigated. Optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction spectroscopy (XRD) were used to characterize the microstructures and phase constitutions of the cast and rolled alloys. Room temperature tensile tests were conducted to obtain the mechanical properties and macro-textures to evaluate the texture weakening effect results of the MM. The results show that an abundance of second phase formed, confirmed as the (Ca,MM)MgSn phase, and the volume fraction increased with the increasing MM addition. The tensile yield strength of the as-cast alloys increased with the MM addition, but the elongation decreased. All of the rolled Mg–3Sn–0.1Ca–xMM alloys showed a strong basal texture, and only slightly decreased in intensity after annealing treatment due to the particle-stimulated nucleation of recrystallization. The as-annealed Mg–3Sn–0.1Ca–0.6MM alloys exhibited the highest tensile strengths of 266.5 ± 3.3 MPa and 136.1 ± 3.7 MPa, which are mainly ascribed to grain refinement strengthening, Orowan strengthening and texture strengthening. Full article

Gadolinium aluminate perovskite (GdAlO₃) was studied at high pressures of up to 23 GPa in a diamond anvil cell (DAC) using monochromatic synchrotron X-ray powder diffraction. Evidence of a pressure-induced phase transformation from orthorhombic (Pbnm) to rhombohedral (R$\overline{3}$c) structure was observed at 21 GPa and further proved by DFT calculations. Before phase transition, the volumetric ratio of polyhedron A and B (i.e., V_A/V_B for ABX₃ general notation) in the Pbnm phase continuously increased towards the ideal value of five at the transition, indicating a pressure-induced decrease in the structural distortion as opposed to the trend in many other orthorhombic perovskites (e.g., CaSnO₃, CaGeO₃, MgSiO₃ and NaMgF₃). Pressure–volume data of the Pbnm phase were fitted to the third-order Birch–Murnaghan equation of state yielding a bulk modulus (K_o) of 216 ± 7 GPa with a pressure derivative of the bulk modulus ($K_o^{\prime }$) of 5.8 GPa (fixed). This work confirms the pressure-induced phase transformation from orthorhombic to a higher symmetry structure previously predicted in GdAlO₃ perovskite. Full article

The effects of Al addition on the microstructure and mechanical properties of Mg-Zn-Sn-Mn-Ca alloys are studied in this paper. It was found that the Mg-6Sn-4Zn-1Mn-0.2Ca-xAl (ZTM641-0.2Ca-xAl, x = 0, 0.5, 1, 2 wt.%; hereafter, all compositions are in weight percent unless stated otherwise) alloys have α-Mg, Mg₂Sn, Mg₇Zn₃, MgZn, α-Mn, CaMgSn, AlMn, Mg₃₂(Al,Zn)₄₉ phases. The grain is also refined when the Al element is added, and the angular-block AlMn phases are formed in the alloys. For the ZTM641-0.2Ca-xAl alloy, the higher Al content is beneficial to elongation, and the double-aged ZTM641-0.2Ca-2Al alloy has the highest elongation, which is 13.2%. The higher Al content enhances the high-temperature strength for the as-extruded ZTM641-0.2Ca alloy; overall, the as-extruded ZTM641-0.2Ca-2Al alloy has the best performance; that is, the tensile strength and yield strength of the ZTM641-0.2Ca-2Al alloy are 159 MPa and 132 MPa at 150 °C, and 103 MPa and 90 MPa at 200 °C, respectively. Full article

In the present study, the influence of the Zn content (0.0, 0.5, 1.0, and 2.0 wt.%) on the microstructure, texture, tensile mechanical properties and formability of Mg-1.0Sn-0.5Ca-based alloys after extrusion were investigated via extrusion of Mg sheets and analysis of the extruded materials. Adding Zn improved the microstructure uniformity and accelerated the formation of more CaMgSn and the Ca₂Mg₆Zn₃ phase. In addition, after the addition of Zn, the texture evolved from the initial extrusion direction tilted bimodal texture to a weakened and symmetrical texture. Compared with the Mg-1.0Sn-0.5Ca alloy, the average tensile yield strength and elongation values were simultaneously improved after 0.5 wt.% Zn addition due to the synergistic effect of the solid solution of elemental Zn, the decreased amount of coarse unrecrystallized grains, and the existence of an additional tilted direction texture component. The formability first increased and then decreased with increasing Zn content. In contrast, the deterioration of formability after the further addition of Zn was closely associated with the increased volume fractions of the coarse CaMgSn and Ca₂Mg₆Zn₃ phases. Full article

Several ternary- and binary-structured ZnO-based nanocrystallites (Zn₂SnO₄, Zn₂TiO₄, ZnO/SnO₂, ZnO/TiO₂) were synthesized by the solid-state method and first tested as photocatalysts in the removal of fumonisin B₁ (FB₁) under UV irradiation. The phase composition and nanocrystalline dimensions (50–80 nm) were confirmed by X-ray diffraction and Raman analyses. Similar preparation procedures applied in the case of binary structures resulted in their uniform morphology consisting of spherical particles ranging from 100 nm to 1 µm in size. However, higher synthesis temperatures of ternary oxides contributed to the growth of particles up to 10 µm. The optical energy bands of the examined photocatalysts were in the range of 3.08–3.36 eV. The efficiency of photocatalysis was compared with the efficiency of direct and indirect (sensitized by UV/H₂O₂ or UV/S₂O₈²⁻) photolysis. The matrix effect of the different water types (Danube River, ground, and tap water) on the removal efficiency of FB₁ was investigated by applying direct and indirect photolysis, as well as in the presence of the Zn₂SnO₄ photocatalyst. The effects of inorganic anions (Cl⁻, NO₃⁻, HCO₃⁻ and SO₄²⁻), cations (Ca²⁺ and Mg²⁺), and humic acid were also investigated, since they were identified as a major species in tap, ground, and river water. Full article

Non-rare earth doped oxide phosphors with far-red emission have become one of the hot spots of current research due to their low price and excellent physicochemical stability as the red component in white light-emitting diodes (W-LEDs) and plant growth. Herein, we report novel Mn⁴⁺-doped La₂CaSnO₆ and La₂MgSnO₆ phosphors by high-temperature solid-phase synthesis and analyzed their crystal structures by XRD and Rietveld refinement. Their excitation spectra consist of two distinct excitation bands with the dominant excitation range from 250 to 450 nm, indicating that they possess strong absorption of near-ultraviolet light. Their emission is located around 693 and 708 nm, respectively, and can be absorbed by the photosensitive pigments Pr and Pfr, proving their great potential for plant growth. Finally, the prepared samples were coated with 365 nm UV chips to fabricate far-red LEDs and W-LEDs with low correlation color temperature (CCT = 4958 K/5275 K) and high color rendering index (R_a = 96.4/96.6). Our results indicate that La₂CaSnO₆:Mn⁴⁺ and La₂MgSnO₆:Mn⁴⁺ red phosphors could be used as candidate materials for W-LED lighting and plant growth. Full article

In this paper, the effect of Ca and Zr additions on microstructure and mechanical properties at room temperature of Mg-Sn alloys was investigated by comparison of Mg-3Sn (wt.%) (T3), Mg-3Sn-1Ca (wt.%) (TX31), and Mg-3Sn-1Ca-1Zr (wt.%) (TXK311) alloys under extrusion. The results show that the main phases of as-extruded T3 alloy were α-Mg and Mg₂Sn phases, while the CaMgSn phase was formed and the precipitation of Mg₂Sn phase was inhibited in the TX31 and TXK311 alloys due to the addition of the Ca element. Zr did not form intermetallic compounds with other elements but dissolved in the grains of the matrix and became nucleating particles. Incomplete dynamic recrystallization (DRX) occurred in all alloys during hot extrusion. The coarse rod-like and fine block-like mixed CaMgSn phase was observed in α-Mg matrix of as-extruded samples of the TX31 alloy, and the dispersed granular CaMgSn phase was observed in the TXK311 alloy. Ca inhibited the dynamic recrystallization behavior of the alloys, while Zr promoted the dynamic recrystallization behavior. All the as-extruded alloys exhibit typical fiber texture of {0001} basal//ED. With the addition of Ca and Zr elements, the particle stimulated nucleation (PSN) effect excited by the second phase particles gradually weakened the texture. TXK311 alloy has good comprehensive mechanical properties at room temperature, with tensile strength, yield strength, and elongation of 261 MPa, 244 MPa, and 11%, respectively, and the average grain size was 1.8 μm. Grain refinement and second phase dispersion strengthening are considered to play critical roles in the strength optimization of the TXK311 alloy. Full article

The effects of Zn and Cu addition on the microstructure and mechanical properties of the extruded Mg-3Sn-1Ca alloy were systematically studied. The effects of the grain size, texture, type and distribution of the second phase on the mechanical properties of the alloy were analyzed. The mechanical test results show that the addition of Zn and Cu elements can significantly improve the mechanical properties of the alloy. The as-extruded Mg-3Sn-1Ca-1Zn-1Cu alloy has the best comprehensive mechanical properties, and the UTS, YS and E_L are 244 MPa, 159 MPa and 13.4%, respectively. Compared with the Mg-3Sn-1Ca alloy, the UTS and E_L of the Mg-3Sn-1Ca-1Zn alloy are increased by 50 MPa and 132%, respectively. However, the UTS of the TXC311 alloy is increased by 55 MPa, but the ductility of the Mg-3Sn-1Ca-1Cu alloy is far less than that of the Mg-3Sn-1Ca-1Zn alloy, which is mainly attributed to the presence of a large amount of hard and brittle Mg2Cu phase in the alloy. Interestingly, the addition of Zn to Mg-3Sn-1Ca-1Cu alloy can improve the elongation of the alloy, which is due to the solid solution strengthening caused by the Zn element and the formation of small MgZnCu phase with Zn element and the consumption of Mg2Cu phase. Full article

The effects of 1% Zn on the corrosion properties of homogenized Mg-3Sn-1Ca-1Cu alloys were investigated. The corrosion behavior of homogeneous TXC311 and TXCZ3111 alloys in 3.5% NaCl solution was studied by using a hydrogen evolution test, polarization curve and impedance spectrum, and the corrosion properties of the alloys were discussed with considerations relative to microstructure. The results show that the second phases of TXC311 alloy consist of CaMgSn and Mg₂Cu. The corrosion rate is 132 mm·year⁻¹. After the addition of 1% Zn element, the grains are significantly refined, the number of Mg₂Cu phases is reduced and the MgZnCu phases are formed. The corrosion rate of Mg-3Sn-1Ca-1Cu alloy decreased to 80 mm·year⁻¹. TXCZ3111 alloy presents fine grains and a reduced number of Mg₂Cu phases, which improve the stability of the corrosion film and reduce the corrosion rate of the alloy. Therefore, the corrosion resistance of TXCZ3111 alloy is much higher than that of TXC311 alloy. Full article